The process of making something more secure, resistant to attack, or less vulnerable.


A source of potential harm.

Hazard Assessment

Process of determining, for specific areas, the likelihood of the occurrence of potentially-damaging phenomenon of given magnitudes within a specified period of time

Health and Safety

The process by which the wellbeing of all employees, contractors, visitors and the public is safeguarded.

Herd Immunity

Resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals as a result of previous infection or vaccination.


Systems or applications requiring a very high level of reliability and availability.

High-Risk Areas

Areas identified during the risk assessment that are highly susceptible to a disaster situation or might be the cause of a significant disaster.

Horizon Scanning

Systematic examination of potential threats, opportunities and future developments, which might have the potential to create new risks or change the character of risks already identified.

Hot Debrief

A discussion about the issues and concerns held immediately following an exercise.

Hot site

A facility equipped with full technical requirements including IT, telecoms and infrastructure, and which can be used to provide rapid resumption of operations.